Borehole tool



July 20,1943. .I Ale.. w. sewn... Y 2,324,956

BoRnHoL Toon Fnd Nov. 25, 1940 s sheets-'sheet 2- 2a f., |39 v 22 lo |9 `N\|9 "i5 F/G. N I6,

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@bym w' 2a/dl INVENTOR July 20, 1943. B w sEwELL v 2,324,956

` BoREvHoLE TooL Filed Nov. 25, 1940 3 Sheets-Sheet 3 45 F/G. Q

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Patented July 20, 1943 mmm w. Sewell, ruler, om., assigner te Standard il Development Company, a corporation of Delaware Application November 2'5, 1940, serial Ne. 366,955

(cl. Z55-1) 3 Claims.

The present invention is directed to a device for enlarging a section of a borehole.

It is an object of the present invention to provide a tool which will increase the exposed surface in a portion of a bore hole.

It is a further object of the present invention to provide a cutter which will cut vertical slots extending radially from a bore hole, thereby increasing the surface exposed to the formation.

A further object of the present invention is to provide a continuous cutting chain which may be laterally expanded at any selected point in the bore hole to cut vertical slots in the formaltion at selected pointst v Other objects and advantages of the present invention may be seen from a reading of the following description taken i'n conjunction with the accompanying drawings in which Fig. 1 is a cross sectional view of a modification of the present invention;`

Fig. 2 is a cross sectional view taken along line U-H of Fig. 1;

Fig. 3 is a cross sectional view taken along the line IDI-HI of Fig. l; i

Fig. is a fragmentary view showing the arrangement of the gears for driving the cutting chain;

Fig. 5 is a fragmentary view of a portion of the V means controlling the lower end of the cutting chain; l

Fig. 6 is an oblique view of a. portion of a chain as used in the device shown in 4Fig. l.;

Fig. 7 is an oblique view of a portion of the chain provided with roller cutters which may be used with the device; i

Fig, 8 is a fragmentary sectional view of another modiiication of the present invention; and

Fig. 9 is a top View, and

Fig. 10 is a side view of the shape of slots cut in the formation by the devices illustrated.

Referring specifically to the drawingsand first to Fig. 1, a cylindrical body I0 having a slot ii arranged in the median portion thereof is provided at its upper end with a centrally positioned longitudinal passage l2 in which is arranged l shaft i3. The lower portion of body I0 is provided with a central passage I4 in which is slidably arranged a piston l5 provided at its lower end with a gasket i6 to make a Huid-tight joint with the walls of passage I6.

Arranged within the slotted portion il of the body is cutting chain Il carried by top sprockets Il, bottom sprockets I9 andlside sprockets 2li. Upper sprockets I8 are rotatively mounted on laterally extending shaft 2l which, in turn, is fastened to body I0 to prevent longitudinal or lateral movement thereof. Lower sprockets I9 are supported by laterally extending shaft 22 which is supported by bifurcated ends 24 with which piston I5 'is provided. Ends 24 are arranged to t slidingly in grooves d of block I0. Side sprockets are supported by lateral shafts 25. Shafts 2 l 22 and 25 not only support the sprockets upon, which the 4cutting chain Il runs, but also connects at the ends of the four arms 26.

As will be seen from the drawings, the arms 2S being pivoted at the ends'will assume a substantially vertical position when piston I5 is in its lowermost position, but Will form a. parallelo-- gram as the piston i5 travels upwardly, the angles of the.` parallelogram being controlled by the position of piston l5, the higher the position of piston i5, the greater the lateral dimension of the parallelogram. Shaft 2I is journaled for rotation in body lil. Sprockets I8 are securely attached to shaft 2i for rotation therewith. A spur gear 29 also attached to shaft 2i for rotation therewithmeshes with cog gear'29 which, in turn, is secured to laterally extending shaft 3d for rotation. Also attached to shaft 30 for rotation therewith is ring gear 5. Meshing with ring gear 5 is pinion 3i which is attached to the end of shaft i3..

The upper end of shaft i3 ends in a head 32 provided with pipe threads 33 for attachment to a string of drill pipe 9 in the conventional manner. Bearings 34 separate the head 32 from body iii to allow free rotation thereof, and bushing 35 arranged in passage I2 aids in keeping shaft iii in position.

Fluid communication between central passage i4 in which the piston I5 operates and the interior of drill pipe Eis obtained by passage 38 in shaft i3, side ports 3i opening into enlarged space 3B in body lil, longitudinal passages 39 extending downwardly at the sides of slots II and communicating with enlarged portion 40 at the lower end of passage It. Enlarged portion Ill is in uid communication not only with central passage id, but also with side passages 4i which lead upwardly and communicate with slot I i, the ends of passages lli being provided with Iwear resisting ports 32. l

In the modication shown in Figs. l and 2, the lower portion of body Ill is provided with spikes il?, for engagement with the formation at the bottom 0f the bore hole.

The device described above operates in -the following manner. Head 32 is attached to'the lowel,` end of drill pipe 9 by threads 33 in the usual manvtion of the drill string then causes relative rotative motion between shaft I3 and body III which, in turn, operates cutting chain I'l.

Cutting chain Il is laterally extended by fluid pressure from the drill string flowing through the iiuid passages above described to exert pressure on packing I6 to force piston I5 upwardly. 'I'he drilling fluid, however, does not remain static Within the passages, but, in addition to exerting pressure on piston I5, also passes outwardly through passages 4I and upwardly between the walls of the bore hole and the drilling string to vremove the cuttings produced by chain I'I. By continuing the exertion of fluid pressure on the lower end of piston I5 and the rotation of the drill stem the lateral extent of the slot will be increased to the maximum xed by the size of the device. This size may be changed by varying the size of arms 26, the length of cutting chain I3, and the length of piston I5 and passage I4 within which the piston slides.

An oblique view of the cutting chain shown in Fig. l is illustrated in Fig. 6. This is a preferred type of cutting chain to be used in soft formations, but if desired, it may be used in harder formations. However, it will be found advantageous in cutting more diicult formations to use a chain provided with rolling type cutting edges, as illustrated in Fig. 7. It will be understood that the roller cutters shown in this iigure operate on the same principle as the conventional roller cutter rock bits used in the art.

As a further modification of the present invention instead of using spikes at the lower end of bodyv I0 to hold said body against rotation other means may be used. For example, a hydraulically operated packer in uid communication with drilling fluid passing through passages 39 may be substituted as means for preventing the rotation of body I0. Such a modication is illustrated in Fig. 8 of the drawings. An advantage in the use of such an arrangement is that slots may be cut in the formation at any desired point in the bore hole.

Hydraulically operated packers are well known in the art and any conventional type may be used, for example, that shown in U. S. Patent No. 2,098,484, issued November 9, 1937. Packers of this type are set merely by an increase in tubing pressure and are released by a decrease of tubing pressure and may accordingly be readily set or removed at any depth in the borehole, enabling any desired number of slots to be produced at selected depths in the bore hole with one run of tubing.

As shown in Fig. G the lower end of body I0 is provided with cap member 45 arranged to enclose and protect the ends of packer 46 embracing body I0. Packer 46 is constructed of a resilient material, such as rubber, and is provided with inflation chamber 41 in communication with the central passage 40 in`body I0 by means of ports 48.

It wm be manifest that in this modification of the present invention the Idevice arranged at the lower end of a. string of drill pipe is lowered into the desired position in a bore hole. Drilling uid is then pumped down the drill pipe.' The pressure exerted by the drilling fluid inates the packer to hold body III against rotation and, in addition. exerts a force on piston I5 to laterally extend the cutting chain. Rotation of the drill pipe causes the cutting chain to cut a slot in the formation, while circulation of drilling duid serves the several purposes of carrying away cuttings, laterally extending the cutting chain and expanding the packer. When a slot of the desired size is produced, the circulation of drilling iluidis terminated, and the reduced pressure allows lateral contraction of the cutting chain and of the packer so that the device may be placed in another position or removed from the bore hole as desired.

If desired, other suitable means may be used for holding body III againstrotation while the cutting operation is carried out. It will heappreciated that after a slot is begun the cutting means bearing against the formation will operate to prevent rotation of the body I0 and allow the cutting operation to be satisfactorily carried to completion.

While I have disclosed specliic modiiications or the present invention, it will be obvious that changes may be made Without departing from the scope of the invention. It is therefore my intention to claim the invention as broadly as the prior art permits.

I claim:

l. A well slotting device adapted to be secured v to a drill stem, comprising, in combination, an

elongated body, oppositely extensible arms pivoted to said body, hydraulically operated means arranged to extend said arms under pressure transmitted through said drill stem, an endless cutting chain carried by said arms and arranged for longitudinal movement with respect to said body and to be laterally extended by said arms, and means arranged to transmit power from the drill'stem to said chain to drive the chain while the body remains stationary.

2. A Well slotting device adapted to be secured to a drillstem, comprising, in combination, an

elongated body, a plurality of arms pivoted to form a laterally expansible parallelogram mounted on said body, hydraulically operated means arranged for laterally extending said arms upon the transmission of pressure to said means from the-drill stem, an endless cutting chain carried by said arms and arranged for longitudinal movement with respect to said body and to be laterally extended by -said arms, and means arranged to transmit power fromthe drill stem to said chain to drive the chain while the body remains stationary. f

3. A 'device in accordance with claim 2 in which the body is provided with passages in fluid communication with the drill stem and discharging upwardly at points below the lowermost portion of the cutting chain. 1

BENJAMIN W. SEWELL. 

